i915: Enable point sprite coordinate generation
i915: Enable point sprite coordinate generation

Support still isn't completely correct, but it's better.  piglit
point-sprite now passes.  However, glean's pointSprite test fails.  In
that test the texture on the sprite is somehow inverted as though
GL_POINT_SPRITE_COORD_ORIGIN were set to GL_LOWER_LEFT.  i915 hardware
shouldn't be able to do that!

I believe there are also problems when not all texture units have
GL_COORD_REPLACE set.  The hardware enable seems to be all or nothing.

Fixes bug #25313.

djreep81/glsl-optimizer,zeux/glsl-optimizer,KTXSoftware/glsl2agal,benaadams/glsl-optimizer,djreep81/glsl-optimizer,tokyovigilante/glsl-optimizer,tokyovigilante/glsl-optimizer,zz85/glsl-optimizer,adobe/glsl2agal,djreep81/glsl-optimizer,wolf96/glsl-optimizer,adobe/glsl2agal,KTXSoftware/glsl2agal,djreep81/glsl-optimizer,benaadams/glsl-optimizer,bkaradzic/glsl-optimizer,benaadams/glsl-optimizer,metora/MesaGLSLCompiler,zz85/glsl-optimizer,zz85/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,bkaradzic/glsl-optimizer,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,adobe/glsl2agal,wolf96/glsl-optimizer,bkaradzic/glsl-optimizer,metora/MesaGLSLCompiler,jbarczak/glsl-optimizer,jbarczak/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,jbarczak/glsl-optimizer,bkaradzic/glsl-optimizer,adobe/glsl2agal,zeux/glsl-optimizer,mcanthony/glsl-optimizer,mcanthony/glsl-optimizer,mcanthony/glsl-optimizer,zeux/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,benaadams/glsl-optimizer,KTXSoftware/glsl2agal,adobe/glsl2agal,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,mapbox/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,mapbox/glsl-optimizer,jbarczak/glsl-optimizer,wolf96/glsl-optimizer,dellis1972/glsl-optimizer,metora/MesaGLSLCompiler,mcanthony/glsl-optimizer,KTXSoftware/glsl2agal,KTXSoftware/glsl2agal,zz85/glsl-optimizer,dellis1972/glsl-optimizer,mcanthony/glsl-optimizer,dellis1972/glsl-optimizer,tokyovigilante/glsl-optimizer,zz85/glsl-optimizer,benaadams/glsl-optimizer,djreep81/glsl-optimizer,dellis1972/glsl-optimizer